1. Field of the Invention
The present invention relates to a substrate processing apparatus holding a substrate such as a glass substrate for a liquid crystal display or a semiconductor wafer and rotating the same about a vertical axis for performing required processing such as cleaning processing or drying processing.
2. Description of the Background Art
When a processing solution such as an etching solution is supplied to the lower surface of a substrate such as a semiconductor wafer horizontally rotated about a vertical axis, mist of the processing solution scattered during the processing may reach the upper surface of the substrate to adhere thereto or the processing solution supplied to the lower surface of the substrate may reach the upper surface of the substrate from the peripheral edge thereof.
In order to solve this problem, generally proposed is a substrate processing apparatus approaching a blocking member to the upper surface of the substrate for defining a narrow space between the upper surface of the substrate and the blocking member and introducing inert gas such as nitrogen gas into the space thereby preventing the mist of the processing solution or the processing solution from reaching the upper surface of the substrate.
FIG. 9 is a model diagram schematically showing the structure of a principal part of an exemplary conventional substrate processing apparatus having the aforementioned structure. A substrate W is positioned by a plurality of, e.g., three support pins 202 provided on a rotary base member 201, to be horizontally supported. The rotary base member 201, fixed to the upper end of a rotary spindle 203 rotatably supported and rotated about a vertical axis by a motor (not shown), is rotated while holding the substrate W.
A blocking member 204 consisting of a circular plate equivalent in size to the substrate W is arranged above the rotary base member 201, mounted on a suspension arm 205 and horizontally held. The suspension arm 205 is vertically movably supported to be capable of approaching the blocking member 204 to the substrate W and upwardly separating the former from the latter. A gas outlet 206 is provided on the central portion of the blocking member 204 for injecting inert gas such as nitrogen gas toward the upper surface of the substrate W. The suspension arm 205 is formed on its axial portion with a gas introduction passage 207, communicating with the gas outlet 206, connected to a gas supply pipe (not shown).
A processing solution nozzle 208 is arranged under the rotary base member 201 for supplying a processing solution such as an etching solution, a developer or a detergent to the lower surface of the substrate W in response to the contents of processing. A cup (not shown) is vertically movably arranged around the rotary base member 201 for preventing the processing solution from scattering, and a discharge/exhaust pipe is provided on the bottom portion of this cap for discharging the processing solution recovered in the cup from the substrate processing apparatus and exhausting the cup.
In order to process the substrate W in the substrate processing apparatus having the aforementioned structure, the blocking member 204 is approached to the substrate W supported by the support pins 202 provided on the rotary base member 201 for rotating the substrate W and supplying the processing solution to the lower surface of the substrate W. At this time, the inert gas is injected toward the upper surface of the substrate W from the gas outlet 206 of the blocking member 204 to be introduced into and purge the space between the upper surface of the substrate W and the blocking member 204.
The inert gas introduced into the space between the substrate W and the blocking member 204 flows toward the peripheral edge of the substrate W, and is injected outward from the peripheral edge of the substrate W. Therefore, mist of the processing solution scattered from the peripheral edge of the substrate W is forced back by the flow of the inert gas outwardly injected from the peripheral edge of the substrate W not to penetrate into the space between the substrate W and the blocking member 204, and the processing solution supplied to the lower surface of the substrate W is prevented by the flow of the inert gas from reaching the upper surface of the substrate W from the peripheral edge of the substrate W.
However, the prior art having such a structure has the following problems: In the aforementioned substrate processing apparatus approaching the blocking member 204 to the upper surface of the substrate W for purging the space between the substrate W and the blocking member 204 by introducing the nitrogen gas, the blocking member 204 must be approached to the upper surface of the substrate W as close as possible in order to effectively prevent the scattered mist and the processing solution from reaching the upper surface of the substrate W. However, the distance capable of approaching the blocking member 204 to the upper surface of the substrate W without coming into contact with the rotated substrate W is limited due to mechanical accuracy of the blocking member 204. In the structure approaching the blocking member 204 to the upper surface of the substrate W, therefore, the mist of the processing solution or the processing solution cannot necessarily be sufficiently prevented from reaching the upper surface of the substrate W.
Particularly when the substrate processing apparatus processes a large-diameter substrate and supplies the processing solution substantially to the central position of the lower surface of the substrate, the central portion of the substrate is convexly protruded due to the injection pressure of the processing solution. Such deformation of the substrate during processing makes approximation of the substrate W and the blocking member 204 further difficult.
The aforementioned substrate processing apparatus is also employed for substrate processing referred to as bevel etching. In this processing, a processing solution Q is discharged toward the lower surface, formed with no device, of a substrate W as shown in FIG. 10 so that the processing solution Q transferred from the center to the periphery of the lower surface centrifugally reaches the upper surface for processing a peripheral area RA of the outer peripheral edge of the upper surface of the substrate W.
Thus, the substrate processing apparatus carries out a substrate processing method of processing the overall lower surface and the outer peripheral edge of the substrate W or the overall lower surface, the outer peripheral edge and the peripheral portion of the upper surface of the substrate W. In other words, the processing solution Q processes only the peripheral portion of the upper surface of the substrate W. More specifically, the substrate processing apparatus processes a substrate plated with copper on the overall upper surface, for removing the copper plating from the overall lower surface and only the peripheral portion of about 1 to 7 mm, for example, of the upper surface.
On the other hand, the conventional support pins 202 supporting the substrate W on the rotary base member 201 include mechanical chucks holding the outer peripheral edge of the substrate W with members consisting of pawls or rings so that the substrate W does not centrifugally spring out. Holding power of the mechanical chucks utilizes mechanical force of urging means consisting of springs or the like. This holding power is canceled by driving cancel means provided on the rotary base member 201.
However, the bevel etching employing such mechanical chucks has the following problem: The plurality of support pins 202 hold the outer peripheral edge of the substrate W during the processing, and hence the processing solution does not reach a part, located in the vicinity thereof, of the peripheral portion of the upper surface of the substrate W. Therefore, the peripheral portion of the upper surface of the substrate W cannot be homogeneously processed.
Further, it follows that the cancel means for the mechanical chucks provided on the rotary base member 201 is soaked with a large quantity of processing solution during the processing. When the cancel means is wetted with the processing solution, a driving system related to the cancel means is corroded to cause a defect in the operation of the cancel means. Therefore, a new chucking system capable of preventing irregular processing is desired.
The present invention is directed to a substrate processing apparatus processing a substrate by supplying a processing solution to the substrate while rotating the same.
According to the present invention, the substrate processing apparatus comprises a proximity suction part injecting gas from a hole provided on a supporting surface opposed to the upper surface of the substrate thereby sucking the substrate through Bernoulli effect, a rotation part rotating the proximity suction part about a vertical axis, a support member uprightly provided on the supporting surface of the proximity suction part for coming into contact with the peripheral portion of the substrate when the proximity suction part sucks the substrate thereby transmitting the driving force of the rotation part to the substrate and a processing solution supply part supplying a processing solution to the lower surface of the substrate rotated in contact with the support member.
Mist of the processing solution or the processing solution can be reliably prevented from reaching the upper surface of the substrate.
Preferably, the substrate processing apparatus further comprises a contact position changing part changing the position of the substrate coming into contact with the contact supporting surface, and the processing solution supply part supplies the processing solution to the substrate before and after changing the position coming into contact with the contact supporting surface.
Homogeneous processing can be performed by preventing irregular processing resulting from holding of the support member.
According to another aspect of the present invention, the substrate processing apparatus comprises a proximity suction part injecting gas from a hole provided on a supporting surface opposed to the upper surface of the substrate thereby sucking the substrate through Bernoulli effect, a rotation part rotating the proximity suction part about a vertical axis, a support member uprightly provided on the supporting surface of the proximity suction part for coming into contact with the upper surface of the substrate when the proximity suction part sucks the substrate thereby transmitting the driving force of the rotation part to the substrate and processing solution supply part supplying a processing solution to the lower surface of the substrate rotated in contact with the support member, while the support member is so arranged that the forward end of the support member comes into contact with a clearance between a processing area where the processing solution supplied to the lower surface of the substrate reaches a peripheral upper surface of the substrate for performing processing and an effective area where a device pattern is formed when the proximity suction part sucks the substrate.
Mist of the processing solution or the processing solution can be reliably prevented from reaching the upper surface of the substrate, and homogeneous processing can be performed by preventing irregular processing resulting from holding of the support member while bringing the support member into contact with the substrate.
Accordingly, an object of the present invention is to provide a substrate processing apparatus capable of reliably preventing mist of a processing solution or the processing solution from reaching the upper surface of a substrate.
Another object of the present invention is to provide a substrate processing apparatus capable of performing homogeneous processing by preventing irregular processing resulting from holding of a substrate.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.